Variable interest entities and securitization activities - Securitized Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Variable interest entities
Current Principal Balance	$ 6,898,073	$ 5,858,798
Current principal balance of non-company sponsored securitized loans	1,600	8,000
Consolidated VIEs
Variable interest entities
Current Principal Balance	5,122,620	4,945,099
Carrying value	$ 5,066,833	$ 4,895,364
Weighted Average Rate	6.90%	4.30%
ReadyCap Lending Small Business Trust 2019-2
Variable interest entities
Current Principal Balance	$ 32,175	$ 49,031
Carrying value	$ 32,175	$ 48,518
Weighted Average Rate	7.60%	4.00%
ReadyCap Lending Small Business Trust 2023-3
Variable interest entities
Current Principal Balance	$ 121,527
Carrying value	$ 119,308
Weighted Average Rate	8.50%
Sutherland Commercial Mortgage Trust 2017-SBC6
Variable interest entities
Current Principal Balance	$ 1,550	$ 7,386
Carrying value	$ 1,532	$ 7,273
Weighted Average Rate	5.00%	4.30%
Sutherland Commercial Mortgage Trust 2019-SBC8
Variable interest entities
Current Principal Balance	$ 105,281	$ 120,916
Carrying value	$ 103,733	$ 119,072
Weighted Average Rate	2.90%	2.90%
Sutherland Commercial Mortgage Trust 2021-SBC10
Variable interest entities
Current Principal Balance	$ 81,214	$ 109,622
Carrying value	$ 79,952	$ 107,969
Weighted Average Rate	1.60%	1.60%
ReadyCap Commercial Mortgage Trust 2015-2
Variable interest entities
Current Principal Balance	$ 1,902	$ 2,726
Carrying value	$ 1,753	$ 2,442
Weighted Average Rate	5.10%	5.10%
ReadyCap Commercial Mortgage Trust 2016-3
Variable interest entities
Current Principal Balance	$ 9,038	$ 11,950
Carrying value	$ 8,723	$ 11,787
Weighted Average Rate	5.20%	5.10%
ReadyCap Commercial Mortgage Trust 2018-4
Variable interest entities
Current Principal Balance	$ 53,052	$ 58,838
Carrying value	$ 51,309	$ 57,857
Weighted Average Rate	4.50%	4.30%
ReadyCap Commercial Mortgage Trust 2019-5
Variable interest entities
Current Principal Balance	$ 88,520	$ 111,184
Carrying value	$ 83,529	$ 108,859
Weighted Average Rate	4.70%	4.50%
ReadyCap Commercial Mortgage Trust 2019-6
Variable interest entities
Current Principal Balance	$ 199,379	$ 209,930
Carrying value	$ 195,496	$ 207,464
Weighted Average Rate	3.40%	3.30%
ReadyCap Commercial Mortgage Trust 2022-7
Variable interest entities
Current Principal Balance	$ 195,866	$ 197,498
Carrying value	$ 188,995	$ 194,456
Weighted Average Rate	4.20%	4.20%
Ready Capital Mortgage Financing 2019-FL3
Variable interest entities
Current Principal Balance		$ 59,508
Carrying value		$ 59,508
Weighted Average Rate		3.50%
Ready Capital Mortgage Financing 2020-FL4
Variable interest entities
Current Principal Balance		$ 192,419
Carrying value		$ 192,213
Weighted Average Rate		4.80%
Ready Capital Mortgage Financing 2021-FL5
Variable interest entities
Current Principal Balance	$ 273,681	$ 415,166
Carrying value	$ 273,623	$ 413,101
Weighted Average Rate	6.60%	3.10%
Ready Capital Mortgage Financing 2021-FL6
Variable interest entities
Current Principal Balance	$ 417,782	$ 502,220
Carrying value	$ 416,467	$ 497,891
Weighted Average Rate	6.40%	2.90%
Ready Capital Mortgage Financing 2021-FL7
Variable interest entities
Current Principal Balance	$ 586,117	$ 743,848
Carrying value	$ 583,771	$ 738,246
Weighted Average Rate	6.70%	3.20%
Ready Capital Mortgage Financing 2022-FL8
Variable interest entities
Current Principal Balance	$ 808,671	$ 913,675
Carrying value	$ 805,220	$ 906,307
Weighted Average Rate	7.00%	3.70%
Ready Capital Mortgage Financing 2022-FL9
Variable interest entities
Current Principal Balance	$ 511,622	$ 587,722
Carrying value	$ 505,917	$ 579,823
Weighted Average Rate	8.10%	5.90%
Ready Capital Mortgage Financing 2022-FL10
Variable interest entities
Current Principal Balance	$ 654,116	$ 651,460
Carrying value	$ 646,141	$ 642,578
Weighted Average Rate	7.80%	7.90%
Ready Capital Mortgage Financing 2023-FL11
Variable interest entities
Current Principal Balance	$ 473,481
Carrying value	$ 468,307
Weighted Average Rate	8.20%
Ready Capital Mortgage Financing 2023-FL12
Variable interest entities
Current Principal Balance	$ 507,646
Carrying value	$ 500,882
Weighted Average Rate	8.00%